Topsheet for absorbent article

• US 20030143376A1
• Filed: 12/26/2002
• Published: 07/31/2003
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: KAO Corporation
• Original Assignee: KAO Corporation
• Inventors: Uchiyama, Taiki, Sakamoto, Noriko, Toyoshima, Yasuo, Asano, Koji, Sugiura, Hiroko
• Granted Patent: US 7,569,264 B2
• Time in Patent Office: Days
• US Class Current: 428/156
• CPC Class Codes: A61F 13/51104 the top sheet having a three-dimensional cross-section, e.g. corrugations, embossments, recesses or projections
• CPC Class Codes: A61F 13/5116 being formed of multiple layers A61F13/5123 takes precedence
• CPC Class Codes: A61F 13/513 characterised by its function or properties, e.g. stretchability, breathability, rewet, visual effect; having areas of different permeability
• CPC Class Codes: A61F 2013/51178 with the combination of nonwoven webs
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/24595 and varying density
• CPC Class Codes: Y10T 428/2481 including layer of mechanically interengaged strands, strand-portions or strand-like strips
• CPC Class Codes: Y10T 428/24826 Spot bonds connect components

Abstract

A topsheet for absorbent articles having absorbing performance for smoothly transferring liquid body waste, e.g., menstrual blood or urine, to an underlying absorbent member and surface characteristics such that the surface thereof in contact with wearer'"'"'s skin is soft enough not to cause skin irritation. The topsheet 1 comprises a first layer 11 disposed on the side of a wearer and a second layer 12 disposed on the side of an absorbent member, the first layer and the second layer being partly joined together, and having protrusions and depressions on the side of a wearer, wherein the first and second layers each comprise a fiber aggregate, the first layer has fusion-bonded fiber intersections, the first layer has an apparent thickness (t1) of 0.1 to 5 mm, the second layer has an apparent thickness (t2) of 0.2 to 3 mm, the apparent thickness ratio of the first layer to the second layer (t1/t2) is 0.5 to 8, the first layer has a fiber density (d1) of 0.001 to 0.05 g/cm³, the second layer has a fiber density (d2) of 0.03 to 0.2 g/cm³, and the fiber density (d2) of the second layer is higher than that (d1) of the first layer.

Claims

1. A topsheet for an absorbent article comprising a first layer disposed on the side of a wearer and a second layer disposed on the side of an absorbent member, the first layer and the second layer being partly joined together, and having protrusions and depressions on the side of a wearer, wherein said first layer and said second layer each comprise a fiber aggregate, said first layer has fusion-bonded fiber intersections, said first layer has an apparent thickness (t1) of 0.1 to 5 mm, said second layer has an apparent thickness (t2) of 0.2 to 3 mm, the apparent thickness ratio of said first layer to said second layer (t1/t2) is 0.5 to 8, said first layer has a fiber density (d1) of 0.001 to 0.05 g/cm³, said second layer has a fiber density (d2) of 0.03 to 0.2 g/cm³, and the fiber density (d2) of said second layer is higher than the fiber density (d1) of said first layer.

2. The topsheet according to claim 1, wherein said first layer and said second layer are in contact with each other in not only the joint areas but other parts.

3. The topsheet according to claim 1, wherein the ratio of the fiber density d2 of said second layer to the fiber density dl of said first layer, d2/d1, is 1.2 or higher.

4. The topsheet according to claim 1, wherein said second layer has a higher capillary rise according to the Klemm method than said first layer.

5. A process of producing a topsheet for an absorbent article according to claim 1, which comprises subjecting a nonwoven fabric having fusion-bonded fiber intersections to a hot air treatment to form a bulky nonwoven fabric having an apparent density of 0.004 to 0.05 g/cm³ and a thickness of 0.3 to 5 mm, superposing the bulky nonwoven fabric as a first layer-forming material and a fiber aggregate as a second layer-forming material on each other, partly joining the first layer-forming material and the second layer-forming material to form a composite sheet, and shrinking the second layer-forming material in the horizontal direction.

6. The process of producing a topsheet for an absorbent article according to claim 5, wherein said fiber aggregate as a second layer-forming material is a fiber aggregate containing fiber capable of shrinking when subjected to a treatment, and the step of shrinking the second layer-forming material is carried out by said treatment.

7. The process of producing a topsheet for an absorbent article according to claim 6, wherein said fiber capable of shrinking when subjected to a treatment is self-crimping fiber capable of crimping itself when subjected to a heat treatment.

8. An absorbent article comprising a liquid permeable topsheet, a liquid impermeable backsheet, and a liquid retentive absorbent member interposed between the topsheet and the backsheet, wherein:

said topsheet comprises a first layer disposed on the side of a wearer and a second layer disposed on the side of an absorbent member and has protrusions and depressions on the side of a wearer,

said first layer comprises a fiber aggregate having fusion-bonded fiber intersections,

said first layer has an apparent thickness (t1) of 0.1 to 5 mm, said second layer has an apparent thickness (t2) of 0.2 to 3 mm, the apparent thickness ratio of said first layer to said second layer (t1/t2) is 0.5 to 8, said topsheet shows a through-thickness deformation of 0.03 to 0.3 mm per gf/cm² when compressed under a load of 10 gf/cm², and said topsheet has a surface whiteness of 60 or higher in terms of L value and a red plate hiding ratio of 40% or higher.

9. The absorbent article according to claim 8, wherein the difference between the surface whiteness La, in terms of L value, of the absorbent article before liquid absorption and the surface whiteness Lb, in terms of L value, of the absorbent article after absorbing 6 g of simulated blood, La-Lb, is 40 or smaller, and the Lb is 60 or higher.